JP5338740B2 - Cleaning device and image forming apparatus - Google Patents

Description

  The present invention relates to a cleaning device and an image forming apparatus.

  2. Description of the Related Art Many image forming apparatuses that form images on paper with toner use cleaning blades that are inexpensive and have high cleaning performance as cleaning apparatuses that clean belt members such as a transfer belt and an intermediate transfer belt. There is also a cleaning device provided with a seal member that is installed upstream of the cleaning raid in the rotation direction of the belt member to prevent the toner from scattering during the cleaning operation by the cleaning blade. (For example, patent document 1).

Japanese Patent Laid-Open No. 2002-40894

  The belt member in the image forming apparatus may adhere to a foreign substance having viscosity and strong cohesion in addition to the toner. For example, when the belt member is a transfer belt that transfers a toner image from an image carrier onto a sheet, an image formed on the surface of the sheet is in contact with the transfer belt during double-sided printing, and the wax that floats on the image surface is treated as a foreign matter. May adhere to.

  The toner adhering to the belt member can be removed cleanly by the cleaning blade, but cannot be removed by the cleaning blade if a viscous and cohesive foreign matter adheres to the belt member. In some cases, the foreign matter may be interposed between the belt member and the cleaning blade, preventing the cleaning operation by the cleaning blade, or the foreign matter may form a film to increase the frictional force of the cleaning blade and cause the blade to turn over. Will be.

  Even with a cleaning device provided with a seal member as in the technique described in Patent Document 1, it is impossible to remove a foreign substance having a strong cohesive force by the seal member.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a cleaning device and an image forming apparatus that remove foreign matters adhering to a belt member and suppress cleaning failure and blade turning by a cleaning blade.

In order to achieve the above object, a cleaning device according to the present invention comprises:
A cleaning blade for removing toner adhering to the surface of the belt member;
A seal member that is installed upstream of the cleaning blade in the rotation direction of the belt member and suppresses scattering of the toner removed by the cleaning blade by contacting the surface of the belt member;
A tension roller that faces the seal member and stretches the belt member from the back side of the belt member;
The belt member is installed upstream of the cleaning blade and downstream of the seal member in the rotation direction of the belt member, and is in contact with the surface of the belt member in a counter direction with respect to the rotation direction of the belt member. A removal member that removes foreign matter adhering to the surface,
The Young's modulus of the removal member is higher than the Young's modulus of the cleaning blade,
In the rotational direction of the belt member, the removal member is in contact with the surface of the belt member on the downstream side of the position where the tension roller is in contact with the belt member,
The removal member is in surface contact with the surface of the belt member.

An image forming apparatus according to the present invention is
It has the cleaning device, and forms an image on a sheet using toner.

  According to the cleaning device and the image forming apparatus according to the present invention, it is possible to remove foreign matters adhering to the belt member, and to suppress cleaning failure and blade turning by the cleaning blade.

1 is an overall configuration diagram of an image forming apparatus according to the present invention. It is an expanded sectional view of a transfer belt and a cleaning device. It is an expanded sectional view around a removal member. It is explanatory drawing which shows a belt unit and a cleaning unit. It is explanatory drawing which shows the state with which the belt unit and the cleaning unit were integrated.

[Outline of image forming apparatus]
FIG. 1 is an overall configuration diagram of an image forming apparatus 1 according to the present invention.

  In the image forming apparatus 1, a charging unit 20, an image exposing unit 30, a developing unit 40, a transfer belt (belt member) 50, and a cleaning unit 60 are arranged around a rotating image carrier 10. After the charging unit 20 uniformly charges the surface of the image carrier 10, exposure scanning based on image data read from the document by the laser beam of the image exposure unit 30 or print data from the computer is performed to perform latent charging. An image is formed, and the latent image is reversely developed by the developing unit 40 to form a toner image on the surface of the image carrier 10.

  The sheet S fed from the sheet storage section 70A is conveyed to the transfer position, and the toner image is transferred onto the sheet S by the transfer belt 50 at the transfer position. Thereafter, the charge on the back surface of the sheet S is erased and separated from the image carrier 10 and is transported by the transport unit 70B. The fixing unit 80 heat-fixes the toner image on the paper S, and the paper S on which the toner image is heat-fixed is discharged to the paper discharge tray 90 by the paper discharge roller 70C.

  When image formation is performed on both sides of the sheet S, the sheet S heated and fixed by the fixing unit 80 is branched from the normal sheet discharge path by the conveyance path switching plate 70D. An image is formed on the reverse side of the paper S that is switched back and turned upside down in the reverse conveyance unit 70E, passes through the fixing unit 80, and is then discharged to the paper discharge tray 90 by the paper discharge roller 70C.

  Below the transfer belt 50, a cleaning device 100 for removing toner and the like attached to the transfer belt 50 is installed. The surface of the transfer belt 50 is always kept clean by the cleaning device 100, and the paper S discharged from the image forming apparatus 1 is not soiled by toner or the like.

  Next, the structure of the transfer belt 50 and the cleaning device 100 will be described in detail.

[Overview of transfer belt and cleaning device]
FIG. 2 is an enlarged cross-sectional view of the transfer belt 50 and the cleaning device 100.

  As shown in FIG. 2, the transfer belt 50 is stretched by a plurality of rollers, and the transfer belt 50 rotates in the direction of the arrow in FIG. A transfer roller 52 is installed at a position facing the image carrier 10, and the toner image on the image carrier 10 is transferred to the paper S at a position where the image carrier 10 and the transfer roller 52 </ b> A face each other. The material of the transfer belt 50 is polyimide, and the thickness of the transfer belt is 100 μm.

  The cleaning device 100 installed below the transfer belt 50 mainly includes a cleaning blade 101, a toner storage roller 102, a toner discharge regulating member 103, a casing 104, a conveying screw 105, a seal member 106, and a removing member 107. .

  The cleaning blade 101 removes toner adhering to the surface of the transfer belt 50. The cleaning blade 101 faces the stretch roller 53 and is in contact with the surface of the transfer belt 50 in a counter direction with respect to the rotation direction of the transfer belt 50. The material of the cleaning blade 101 is urethane rubber, and the thickness of the cleaning blade 101 is 2 mm. The free length of the cleaning blade is 9 mm, and the contact pressure of the cleaning blade 101 against the transfer belt 50 is 30 N / m.

  In order to prevent the cleaning blade 101 from turning over, a toner reservoir T is formed by the toner storage roller 102 and the toner discharge regulating member 103, and toner is constantly supplied to the edge of the cleaning blade 101 (toner storage roller 102 and toner discharge). The regulating member 103 corresponds to the “toner reservoir forming portion” in the present invention).

  The toner discharge regulating member 103 is a flexible member, and a part of the toner discharge regulating member 103 is in contact with the surface of the toner storage roller 102. Part of the toner removed by the cleaning blade 101 passes between the toner storage roller 102 and the toner discharge regulating member 103 and falls below the casing 104. The toner collected below the casing 104 is collected at one place by the conveying screw 105 and discarded.

  The seal member 106 is installed on the upstream side of the cleaning blade 101 in the rotation direction of the transfer belt 50. The seal member 106 is a flexible member, and the seal member 106 is curved and is in contact with the transfer belt 50. Therefore, the interior of the cleaning device 100 is sealed by the seal member 106 on the upstream side of the cleaning blade 101, and the transfer belt 50 is not soiled by the scattering of toner. The material of the seal member 106 is polyethylene, and the free length of the seal member 106 is 5 mm.

  The toner adhering to the transfer belt 50 is removed by the cleaning blade 101, but the foreign substance having viscosity and strong cohesive force adhering to the transfer belt 50 is removed by the removing member 107. As shown in FIG. 2, the removal member 107 is installed upstream of the cleaning blade 101 and downstream of the seal member 106 in the rotation direction of the transfer belt 50, and is transferred in the counter direction with respect to the rotation direction of the transfer belt 50. It is in contact with the surface of the belt 50.

  FIG. 3 is an enlarged cross-sectional view around the removal member 107.

  The transfer belt 50 contacts the image formed on the surface of the paper S during the reverse side printing of double-sided printing, and the wax that floats on the image surface may adhere to the transfer belt 50 as foreign matter X (foreign matter having viscosity and strong cohesive force). . A removal member 107 is installed separately from the cleaning blade 101 and the seal member 106 to remove the foreign matter.

  The material of the removing member 107 is polyethylene terephthalate, and has a flat plate shape. The material of the removing member 107 may be a resin material other than polyethylene terephthalate, or a metal thin plate or the like.

  The Young's modulus of the removing member 107 is higher than the Young's modulus of the cleaning blade 101. Specifically, the Young's modulus of the removing member 107 is 4 GPa (preferably 1 GPa or more), and the Young's modulus of the cleaning blade 101 is 7 MPa. . Since the removing member 107 is harder than the cleaning blade 101, the foreign matter X having a strong cohesive force such as wax can be removed from the transfer belt 50. Note that the Young's modulus of the sealing member 106 is lower than the Young's modulus of the cleaning blade 101 in consideration of sealing properties, and is specifically 1.5 MPa.

  In consideration of the cleaning property with respect to the foreign matter X, in addition to the material of the removing member 107 and the Young's modulus, the contact condition of the removing member 107 with respect to the transfer belt 50 is determined. This point will be described in detail with reference to FIG.

  In FIG. 3, “a” is the length of the portion where the stretching roller 54 is in contact with the transfer belt 50, and “b” is the end of the portion where the stretching roller 54 is in contact with the transfer belt 50 and the removal member 107. This is the distance from the tip EG. “C” is the length of the portion where the removal member 107 is in contact with the transfer belt 50.

  In order to remove the foreign matter X adhering to the transfer belt 50, it is necessary to abut the removal member 107 against the transfer belt 50 with a constant load and to prevent the tip EG of the removal member 107 from separating from the transfer belt 50. (Because the tip EG scrapes off the foreign matter X from the transfer belt 50).

  It is quite difficult in terms of accuracy to make only the front end EG of the removal member 107 contact the transfer belt 50. Further, when the removing member 107 is brought into contact with the transfer belt 50 with a constant load on the surface opposite to the portion where the stretching roller 54 is in contact with the transfer belt 50, the leading end EG of the removing member 107 is warped and the leading end EG becomes the transfer belt. There is a possibility of moving away from 50.

  Therefore, in the image forming apparatus 1 according to the present invention, the removal member 107 is brought into contact with the surface of the transfer belt 50 on the downstream side of the position where the stretching roller 54 is in contact with the transfer belt 50 in the rotation direction of the transfer belt 50. I am letting. Since the removing member 107 is brought into contact with the transfer belt 50 at the downstream side from the position where the stretching roller 54 is in contact with the transfer belt 50, that is, at the position where the stretching roller 54 is not in contact with the transfer belt 50, The front end EG of the removing member 107 comes into contact with the transfer belt 50 without the front end EG warping.

  Further, as indicated by “c” in FIG. 3, since the removing member 107 is in surface contact with the transfer belt 50 with a certain width, even if the transfer belt 50 and the cleaning device 100 are assembled unevenly, At least the tip EG of the removal member 107 does not leave the transfer belt 50.

  In addition, when the contact pressure of the removal member 107 with respect to the transfer belt 50 was examined through experiments, it was found that the contact pressure is preferably within a range of 10 to 65 mN / cm, and particularly preferably within a range of 15 to 60 mN / cm. . This is because when the contact pressure is low, the cleaning performance of the removing member 107 is deteriorated, and when the contact pressure is high, the toner supplied to the cleaning blade 101 is reduced, and problems such as blade turning are likely to occur. In this embodiment, the contact pressure is 30 mN / cm.

  Further, when “c” in FIG. 3, which is the length of the portion where the removing member 107 is in contact with the transfer belt 50, was examined through an experiment, it was preferably in the range of 0.5 to 4.0 mm, particularly 1.0 to. It was found that the range of 3.5 mm was preferable. If it is less than 0.5 mm, depending on the assembly of the cleaning device 100, the tip of the removal member 107 may not contact the transfer belt 50, and if it exceeds 4.0 mm, the transfer belt 50 is damaged by the removal member 107. It is. In this embodiment, “c” in FIG. 3 is 2.5 mm.

  In addition, if the length of “b + c” in FIG. 3 exceeds 10 mm, the transfer belt 50 may be swelled, and the leading edge EG of the removal member 106 may be separated from the transfer belt 50. It is preferable to set to. In the present embodiment, the length of “b + c” in FIG. 3 is 7 mm.

  By bringing the removing member 107 into contact with the transfer belt 50 so as to satisfy the above-described conditions, foreign matters having high viscosity and cohesive force are removed from the transfer belt 50, thereby suppressing cleaning failure and blade turning by the cleaning blade. I can do it.

  In particular, in the cleaning device 100 that forms the toner reservoir T as in the present embodiment, if a foreign matter enters the toner reservoir T, there is a high probability that a cleaning failure or blade turning will occur. More effective.

  Further, since the transfer belt 50 transfers the toner image on the image carrier 10 to the paper S and transports the paper as a paper transport member, the transfer belt 50 is kept clean by providing the removal member 107. Paper S can be output neatly. Therefore, it is more effective to bring the removal member 107 into contact with the transfer belt 50.

[Unitization of transfer belt and cleaning device]
The transfer belt 50 and the cleaning device 100 are each unitized, and this point will be described with reference to FIGS.

  FIG. 4 is an explanatory view showing the belt unit and the cleaning unit, and FIG. 5 is an explanatory view showing a state in which the belt unit and the cleaning unit are integrated.

  FIG. 4A shows a belt unit, in which a transfer belt 50 and a plurality of rollers that stretch the transfer belt 50 are fixed by a side plate 500 to form a unit. FIG. 4B shows a cleaning unit, in which at least the cleaning blade 101, the seal member 106, and the removal member 107 are unitized.

  Then, as shown in FIG. 5, the belt unit and the cleaning unit are fixed to the positioning member UT. Thus, since the transfer belt 50 and the cleaning device 100 are each unitized and are fixed by the positioning member UT, at least the removal member 107 and the transfer belt 50 can be positioned easily.

  As mentioned above, although this invention was demonstrated using FIGS. 1-5, this invention is not limited to the said embodiment, Even if there exists a change and addition in the range which does not deviate from the summary of this invention, it is in this invention. included.

  In the present embodiment, the transfer belt is used as the belt member. However, other belt members such as an intermediate transfer belt may be used.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 Image carrier 20 Charging part 30 Image exposure part 40 Developing part 50 Transfer belt 51 Drive roller 52 Transfer roller 53, 54 Stretching roller 100 Cleaning device 101 Cleaning blade 102 Toner storage roller 103 Toner discharge regulating member 104 Casing 105 Conveying screw 106 Sealing member 107 Removal member 500 Side plate UT Positioning member

Claims (6)

A cleaning blade for removing toner adhering to the surface of the belt member;
A seal member that is installed upstream of the cleaning blade in the rotation direction of the belt member and suppresses scattering of the toner removed by the cleaning blade by contacting the surface of the belt member;
A tension roller that faces the seal member and stretches the belt member from the back side of the belt member;
The belt member is installed upstream of the cleaning blade and downstream of the seal member in the rotation direction of the belt member, and is in contact with the surface of the belt member in a counter direction with respect to the rotation direction of the belt member. A removal member that removes foreign matter adhering to the surface,
The Young's modulus of the removal member is higher than the Young's modulus of the cleaning blade,
In the rotational direction of the belt member, the removal member is in contact with the surface of the belt member on the downstream side of the position where the tension roller is in contact with the belt member,
The cleaning device, wherein the removing member is in surface contact with the surface of the belt member.   The cleaning device according to claim 1, further comprising a toner reservoir forming portion that forms a toner reservoir for supplying toner to an edge portion of the cleaning blade.   The cleaning device according to claim 1, wherein a Young's modulus of the seal member is lower than a Young's modulus of the cleaning blade.   The cleaning device according to claim 1, wherein the belt member is a sheet conveying member that conveys a sheet. A belt unit having the belt member and the stretching roller;
A cleaning unit that is separate from the belt unit and has the cleaning blade, the seal member, and the removal member;
A positioning member for fixing the belt unit and the cleaning unit, and positioning at least the belt member and the removal member;
The cleaning device according to claim 1, comprising:   An image forming apparatus comprising the cleaning device according to claim 1, wherein an image is formed on a sheet using toner.

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